Question: Evaluate the following expression when $c = 3$ and $d = 7$. $4$ $c$ $ + 5$ $d$ $ - 9$
Answer: Substitute $3$ for ${c}$ and $7$ for ${d}$ $ = 4{(3)} + 5{(7)} - 9 $ $ = 12 + 35 - 9 $ $ = 38$